Description

It should be possible to produce a graph like this using graphlib.php, and a single database query, so I think we should, and display it after the results table. It should count the number of attempts with a score in each of an appropriate number of score brackets, depending on the quiz total score.

So perhaps we should actually be querying the quiz_grades table and not the attempts table. I'm thinking that the graph should respect the group selected too and display only grades for the group members.

Jamie Pratt
added a comment - 06/May/08 8:52 PM So perhaps we should actually be querying the quiz_grades table and not the attempts table. I'm thinking that the graph should respect the group selected too and display only grades for the group members.

Well, what I think would be nicest is a bar chart showing the numbers for the whole course in one colour, then drawn over the top in another colour, the numbers for this group. (Since the group bars will always be shorter, this will work.) If that is quite easy to do, do it.

The main use for this though is to let people, even if they are not allowed to see scores for everyone in the course, to still get a rough impression for how their group compares to the whole course.

Tim Hunt
added a comment - 06/May/08 9:54 PM Well, what I think would be nicest is a bar chart showing the numbers for the whole course in one colour, then drawn over the top in another colour, the numbers for this group. (Since the group bars will always be shorter, this will work.) If that is quite easy to do, do it.
The main use for this though is to let people, even if they are not allowed to see scores for everyone in the course, to still get a rough impression for how their group compares to the whole course.

Jamie Pratt
added a comment - 07/May/08 10:52 PM I added a graph to the bottom of the overview report. It displays group grades (if you are viewing results for a group) as well as grades for all participants.

I have to express concern about showing groups on the same graph as we show the whole cohort. For courses where we have large cohorts I do not think that we can show the whole cohort and the group on the same graph with the same axes.

For an example let's assume a course with 1,000 students.
And the graph broken in 20 ranges each of 5%.
Then we might easily imagine that >100 students will be in one of the ranges.

Now our tutor groups only have 20 students.
Taking the same proportions as above that translates into 2 students in a range.

And showing 2 students on the same axis as we show >100 will render the former as almost 'not there'.

So I don't want this left as it is.

Which raises the question of what we should do. The points are labelled only so that I can refer back to them below.

[option 1] Let's be clear that the main purpose of this graph is for course teams to get a pictorial view of how the assessment has performed. That is we are mainly interested in 'Course staff' viewing the graph of the whole cohort.

[option 2] Once we have this it is quite OK, and I think helpful, to show that graph to tutors of groups..

If we can easily show tutors where their students sit then that is worthwhile but as I've pointed out we can't do it using the same scales.[option 3a] So either there will need to be two y scales, one for the cohort and one for the group ( I don't know that I like this).[option 3b] Or we should arrange a graph for the group below that for the cohort and positioned so that shapes of the graphs can be compared.

[option 4] We should not try to show all groups on one graph. A course population of 1,000 translates into 50 tutor groups. And we have much bigger courses.

I wish to see [option 1]. This is a requirement.[option 2] follows readily from [option 1].[option 3a/b] would probably be good. But I'd like to see it with reasonable numbers.[option 4] should be dismissed. Course staff can already see how tutor groups perform through the Gradebook. If we wish to reproduce this in the quiz reports we should use the same approach i.e. allow course staff to select a group. But this is not a requirement

Philip Butcher
added a comment - 07/Aug/08 9:37 PM I have to express concern about showing groups on the same graph as we show the whole cohort. For courses where we have large cohorts I do not think that we can show the whole cohort and the group on the same graph with the same axes.
For an example let's assume a course with 1,000 students.
And the graph broken in 20 ranges each of 5%.
Then we might easily imagine that >100 students will be in one of the ranges.
Now our tutor groups only have 20 students.
Taking the same proportions as above that translates into 2 students in a range.
And showing 2 students on the same axis as we show >100 will render the former as almost 'not there'.
So I don't want this left as it is.
Which raises the question of what we should do. The points are labelled only so that I can refer back to them below.
[option 1] Let's be clear that the main purpose of this graph is for course teams to get a pictorial view of how the assessment has performed. That is we are mainly interested in 'Course staff' viewing the graph of the whole cohort.
[option 2] Once we have this it is quite OK, and I think helpful, to show that graph to tutors of groups..
If we can easily show tutors where their students sit then that is worthwhile but as I've pointed out we can't do it using the same scales.
[option 3a] So either there will need to be two y scales, one for the cohort and one for the group ( I don't know that I like this).
[option 3b] Or we should arrange a graph for the group below that for the cohort and positioned so that shapes of the graphs can be compared.
[option 4] We should not try to show all groups on one graph. A course population of 1,000 translates into 50 tutor groups. And we have much bigger courses.
I wish to see [option 1] . This is a requirement.
[option 2] follows readily from [option 1] .
[option 3a/b] would probably be good. But I'd like to see it with reasonable numbers.
[option 4] should be dismissed. Course staff can already see how tutor groups perform through the Gradebook. If we wish to reproduce this in the quiz reports we should use the same approach i.e. allow course staff to select a group. But this is not a requirement

Did you consider changing the scales to percentages. We could them compare the percentage of students in the group to the percentage of students in all of those who took the test who achieve a grade within the grade band ranges? We would not need different y scales then. This would mean though it would be more difficult to see exactly how many students achieve the grade.

Jamie Pratt
added a comment - 08/Aug/08 7:42 PM Hi Phil,
Did you consider changing the scales to percentages. We could them compare the percentage of students in the group to the percentage of students in all of those who took the test who achieve a grade within the grade band ranges? We would not need different y scales then. This would mean though it would be more difficult to see exactly how many students achieve the grade.
Jamie

Have now seen these graphs and they're OK but might I suggest that if they were smaller in the y dimension then a tutor could view both the graph for their own group and the overall graph on the same screen. At the moment it's only possible to see one graph at a time. Could we do this to make it fit on a 1280 x 1024 screen?

Philip Butcher
added a comment - 18/Aug/08 11:30 PM Have now seen these graphs and they're OK but might I suggest that if they were smaller in the y dimension then a tutor could view both the graph for their own group and the overall graph on the same screen. At the moment it's only possible to see one graph at a time. Could we do this to make it fit on a 1280 x 1024 screen?

Our major use will be for our exams staff to look at the overall distribution for the whole cohort. So the shape matters as does the numbers of students below the pass threshhold. Here they'll only be using the one graph for all participants. So we don't want to make this too small.

However I take Ray's point and as there's a computer behind this that knows how many graphs it is going to draw perhaps Jamie can do the scaling on the fly so that either one graph occupies all the 1028 x 768 or if two graphs are to be shown they are scaled so that together they fit onto 1028 x 768.

Philip Butcher
added a comment - 19/Aug/08 7:08 PM Our major use will be for our exams staff to look at the overall distribution for the whole cohort. So the shape matters as does the numbers of students below the pass threshhold. Here they'll only be using the one graph for all participants. So we don't want to make this too small.
However I take Ray's point and as there's a computer behind this that knows how many graphs it is going to draw perhaps Jamie can do the scaling on the fly so that either one graph occupies all the 1028 x 768 or if two graphs are to be shown they are scaled so that together they fit onto 1028 x 768.